openpgp: Change the hex parsing to accept odd number of nibbles.

  - This came up as the new leak tests use our hex parsing functions
    to parse /proc/self/maps and apparently Linux will drop leading
    zeros from addresses.

  - Fix this by allowing these functions to operate on an odd number
    of nibbles.  I see no reason no reason not to do that, except for
    the fact that we don't want to establish that it is okay to drop
    leading zeros from key IDs and fingerprints, hence I preserved the
    behavior of parsing key IDs and fingerprints.

1 files changed, 5 insertions, 0 deletions

diff --git a/openpgp/src/keyid.rs b/openpgp/src/keyid.rs
index 1c83c63b..2d880706 100644
--- a/openpgp/src/keyid.rs
+++ b/openpgp/src/keyid.rs
@@ -97,6 +97,11 @@ impl std::str::FromStr for KeyID {
     type Err = anyhow::Error;
 
     fn from_str(s: &str) -> std::result::Result<Self, Self::Err> {
+        if s.chars().filter(|c| ! c.is_whitespace()).count() % 2 == 1 {
+            return Err(Error::InvalidArgument(
+                "Odd number of nibbles".into()).into());
+        }
+
         let bytes = crate::fmt::hex::decode_pretty(s)?;
 
         // A KeyID is exactly 8 bytes long.